Mixing shells and mechs - IM SD40T-2 on Kato SD40-2

[johnh35]

Isn't the IM mech basically the Atlas internals with different frame halves to relocate the screws? I have never had one in my hands but that is what I thought was said when it was introduced. I bought a couple of the SD45-2 shells and need a power chassis. It is getting hard (and expensive) to get a Kato SD40-2 donor.

According to the page below, the SD50/SD60 are close to the SD40T-2 and SD45T-2, just about 4" so maybe that is a good solution for the SD40T-2. The problem is the actual fitment of the model. I just tried to put an IM SD40T-2 shell on the Atlas SD50 chassis and it's too long to fit in the shell. It's not even close and since the screw/nut is close to the ends, I don't think milling the ends would work well. I also don't think the Atlas mech is much of an upgrade to the IM. On the other hand, the Kato SD40-2 is better than the IM SD45-2 mech, in my opinion.

Model      CouplerFaces  EndPlates  Bolster C/L
SD40-2    68' 10"           64' 8"        43' 6"
SD45-2    68' 10"           64' 8"        43' 6"

SD50       71' 2"             67'            45' 7 1/2"
SD40T-2  70' 8"             66' 6"        45' 5"

http://www.trainweb.org/utahrails/drgw/locolength.html

[u18b]

John, yes but with a qualifier.

Yes, they are the Atlas parts- but  some of them are the ones we don't prefer.

The HTC truck is the same as always.

But the IM locos I have seen all used the fork and doughnut interface inside the flywheel- like is used on the GP15-1 and the C628 (I think).
I think I remember you were the one years ago who first pointed out that the doughnut can slip with time.

I prefer the hex nut inside the flywheel interface.